Fix QCoroNetwork linking for shared library

[jmiturasolutions]

WaitSignalHelper defined in qcoroiodevice_p.h is used both in core and in network libraries. When using shared linking option, the build fails with log below. Using MSVC 19.29.30140.0 on Windows 10 and Qt 5.15.1.

[15/15] Linking CXX shared library bin\QCoro5Network.dll FAILED: bin/QCoro5Network.dll lib/QCoro5Network.lib cmd.exe /C "cmd.exe /C "E:\.conan\b280e9\1\bin\cmake.exe -E __create_def E:\.conan\ce448f\1\build_subfolder\source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\.\exports.def E:\.conan\ce448f\1\build_subfolder\source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\.\exports.def.objs && cd E:\.conan\ce448f\1\build_subfolder" && E:\.conan\b280e9\1\bin\cmake.exe -E vs_link_dll --intdir=source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir --rc=C:\PROGRA~2\WI3CF2~1\10\bin\100183~1.0\x64\rc.exe --mt=C:\PROGRA~2\WI3CF2~1\10\bin\100183~1.0\x64\mt.exe --manifests -- C:\PROGRA~2\MIB055~1\2019\COMMUN~1\VC\Tools\MSVC\1429~1.301\bin\Hostx64\x64\link.exe /nologo source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\QCoro5Network_autogen\mocs_compilation.cpp.obj source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\qcoroabstractsocket.cpp.obj source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\qcorolocalsocket.cpp.obj source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\qcoronetworkreply.cpp.obj source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\qcorotcpserver.cpp.obj /out:bin\QCoro5Network.dll /implib:lib\QCoro5Network.lib /pdb:bin\QCoro5Network.pdb /dll /version:0.5 /machine:x64 /debug /INCREMENTAL /DEF:source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\.\exports.def lib\QCoro5Core.lib E:\.conan\4d51e9\1\lib\Qt5Network.lib E:\.conan\4d51e9\1\lib\Qt5Core.lib kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib && cd ." LINK Pass 1: command "C:\PROGRA~2\MIB055~1\2019\COMMUN~1\VC\Tools\MSVC\1429~1.301\bin\Hostx64\x64\link.exe /nologo source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\QCoro5Network_autogen\mocs_compilation.cpp.obj source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\qcoroabstractsocket.cpp.obj source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\qcorolocalsocket.cpp.obj source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\qcoronetworkreply.cpp.obj source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\qcorotcpserver.cpp.obj /out:bin\QCoro5Network.dll /implib:lib\QCoro5Network.lib /pdb:bin\QCoro5Network.pdb /dll /version:0.5 /machine:x64 /debug /INCREMENTAL /DEF:source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir\.\exports.def lib\QCoro5Core.lib E:\.conan\4d51e9\1\lib\Qt5Network.lib E:\.conan\4d51e9\1\lib\Qt5Core.lib kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib /MANIFEST /MANIFESTFILE:source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir/intermediate.manifest source_subfolder\qcoro\network\CMakeFiles\QCoro5Network.dir/manifest.res" failed (exit code 1120) with the following output: Creating library lib\QCoro5Network.lib and object lib\QCoro5Network.exp qcoroabstractsocket.cpp.obj : error LNK2001: unresolved external symbol "public: static struct QMetaObject const QCoro::detail::WaitSignalHelper::staticMetaObject" (?staticMetaObject@WaitSignalHelper@detail@QCoro@@2UQMetaObject@@B) qcorolocalsocket.cpp.obj : error LNK2001: unresolved external symbol "public: static struct QMetaObject const QCoro::detail::WaitSignalHelper::staticMetaObject" (?staticMetaObject@WaitSignalHelper@detail@QCoro@@2UQMetaObject@@B) qcoronetworkreply.cpp.obj : error LNK2001: unresolved external symbol "public: static struct QMetaObject const QCoro::detail::WaitSignalHelper::staticMetaObject" (?staticMetaObject@WaitSignalHelper@detail@QCoro@@2UQMetaObject@@B) bin\QCoro5Network.dll : fatal error LNK1120: 1 unresolved externals ninja: build stopped: subcommand failed.